来自《耶鲁大学开放课程：基础物理 第13集 第13集》

• 
  
  and call it Δx2'.
  称之为 Δx'2
• 
  
  Δx' is x2'-x1'.
  Δx' 等于 x'2-x'1
• 
  
  All the Δs will be defined to be 2nd minus the 1st.
  所有的 Δ 都定义为后一个减前一个
• 
  
  I'm telling you to take x1', subtract it from x2'
  在左边 x'2 减掉 x'1
• 
  
  on the left-hand side and call it Δx'.
  称之为 Δx'
• 
  
  Δx' is the difference in the spatial coordinates of
  Δx' 是在你看来的两个事件
• 
  
  the two events according to you.
  在空间坐标系中的差值
• 
  
  If you come to the right-hand side,
  如果你计算右边
• 
  
  now this is something you guys should be able to do in your head.
  大家可以自己心算
• 
  
  I want to subtract that from that.
  我要用这个减去这个
• 
  
  They share the same denominator,
  它们的分母相同
• 
  
  so let me put the denominator there.
  我把分母放在这里